Troubleshooting Motion Sensors - Poor Detection
SiteWorx motion sensors use passive infrared (PIR) technology to detect movement within a field of view. Motion sensor sensitivity is determined by many factors including the direction of motion relative to the sensor, thermal background "noise" and line of sight from target to the motion sensor. In simplified terms, fixtures detect motion based upon heat differentials and the movement of those heat differentials within the sensor field of view.
Factors to consider when evaluating possible causes for poor motion sensor detection include:
- Dust or debris on motion sensor lens?
- Mounting height of motion sensor. Is mounting height within the range noted on the spec sheet for the specific fixture model and motion sensor lens (if applicable)?
- Is the motion occurring within the motion sensor coverage area?
- Is the motion sensor being approached radially or tangentially? Is the fixture located in an open space that does not constrict motion or an aisle that constricts motion to a specific approach? PIR technology is more sensitive to motion tangential to the sensor.
- If issues are associated with radial motion, has micro-adjust been attempted? Further information on micro-adjust as well as radial/tangential motion can be found below.
- Ambient temperature and temperature at fixture height. As the ambient air temperature approaches body temperature, the heat differential between human bodies and the surrounding environment decreases which reduces the ability for motion sensors to detect human motion.
- Is the issue associated with the detection of people or machinery such as forklifts? Are people wearing heavy outer clothing that may insulate heat from being detected by motion sensors? Are hats, protective headgear or PPE present that may insulate heat from motion sensors?
- Machinery or air vents/exhaust nearby?
- Masked or unmasked sensor? Additional information provided below.
Unmasked sensor - allows sensor coverage in all directions.
Masked sensor - limits sensor coverage on minor axis.
Radial vs. Tangential Motion
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